Method of and apparatus for making window envelopes



L. C. PEARC E Sept. 4, 1956 METHOD OF AND APPARATUS FOR MAKING WINDOW ENVELOPES 2 Sheets-Sheet 1 Filed June 19, 1953 IN V EN TOR.

L. C. PEARCE Sept. 4, 1956 METHOD OF AND APPARATUS FOR MAKING WINDOW ENVELOPES Filed June 19, 1953 2 Sheets-Sheet 2 Fig.9

INVEN TOR. LEWIS C. PEARCE United States Patent METHOD OF AND APPARATUS F03 MAKING WINDOW ENVELGPES Lewis C. Pearce, Berea, Ohio, assignor to Pearce Develop ment Company, a corporation of Ohio Application June 19, 1953, Serial No. 362,900

14 Claims. (Cl. 93-61) My invention relates to window envelopes and to a method of, and apparatus for, making the same.

An object of my invention is to provide an improved window envelope having a patch of transparent sheet material adhered to the inner wall of the envelope over the window opening in such manner that mailing material, such as a letter or card, does not catch or hook under the edge of the patch closest to the insertion on entrance of the envelope.

Another object of my invention is to provide an improved window envelope of the type having a patch of transparent sheet material adhered to the inner wall of the envelope in which the edge portion of the patch closest to the opening of the envelope is closely adhered to the envelope wall along said edge to avoid a pocket or non-adhered portion of the patch in which the content of the envelope may engage or catch upon insertion into the envelope.

Another object of my invention is a provision of a mechanism for applying adhesive to an edge portion of a patch of transparent material applied to the inner wall of an envelope blank.

Another object is a provision of a mechanism for applying gum or other adhesive to the trailing edge portion of a patch of transparent material as it is advanced to an envelope blank in the forming of a window envelope.

Another object is a provision of an improved mechanism for applying adhesive between a patch of transparent material and the blank of a window envelope along and adjacent the edge of the blank closet to the insertion entrance of the envelope.

Another object is a provision of a mechanism for applying adhesive to a side of a transparent patch which is to be adhered to an envelope blank and along the edge of the patch to be positioned closest to the insertion entrance.

Another object is a provision of an improved mechanism for applying adhesive to sheet material in the manufacture of envelopes.

Another object is the provision of an improved method for making window envelopes.

Another object is the provision of a method for obtaining the close adherence of a window patch for a window envelope along the edge of the patch closest to the insertion entrance of the envelope.

Another object is the provision of an improve enyelope, method of, and apparatus for, the making of the same, having features, benefits, and advantages heretofore not obtainable.

Other objects and a fuller understanding of this invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a side view of an apparatus embodying my invention having some portions in cross-section for illustrating the relationship of the parts;

Figure 2 is an enlarged view of a portion of my apparatus showing the parts in the position of applying the transparent patch to the envelope blank;

Figure 3 is an enlarged and sectional View of a portion of the apparatus shown in Figure 1 and showing details of the device carrying a transparent patch and gathering adhesive on its trailing edgeportion;

Figure 4 is a view of a portion of the apparatus shown in Figure 1 looking in the direction of the arrows 4-4 of Figure 1;

Figure 5 is a partial view of the apparatus shown in Figure 1 looking in the direction of the arrows 5-5 of Figure 1;

Figure 6 is a plan View with an envelope blank having a window opening cut therein;

Figure 7 is a plan view of an envelope blank similar to that shown in Figure 6 and upon which a first zone of adhesive has been applied around the opening in the blank; 7

Figure 8 is a plan view of an envelope blank having the transparent patch applied to the inner wall of the envelope and showing the relationship of the zones of adhesive between the patch and envelope blank and particularly the last-applied band of adhesive along the edge of the patch closest to the insertion entrance; and

Figure 9 is a view of a completed window envelope embodying my invention and having portions cut away to show the patch of transparent material over the window opening and showing the location of the last-applied band of adhesive along its trailing edge and positioned closet to the insertion entrance of the envelope.

My apparatus includes a usual gum applicator 11 mounted to revolve on the shaft 13 relative to a blank carrying belt 15 so as to apply a rectangular band of adhesive around the rectangular edge of the window opening in an envelope. The applicator 11 obtains or gathers adhesive from a roll 12 arranged to feed adhesive to the applicator in each cycle. As an envelope blank, such as blank 57 shown in Figure 6, moves along on the belt 15 over the lower roll 14, the applicator 11 recurrently comes down to apply a band of adhesive, such as the rectangular band 69 in the zone shown in Figure 7. This rectangular zone in which the adhesive is applied by the applicator 11 extends around the rectangular opening 58, as shown in Figure 7, and is spaced laterally outward from the edge of the opening 58 and is also spaced laterally inwardly from the peripheral edge of the area 59, shown in Figures 6 and 7, to be covered by the transparent patch 27. The rectangular zone 60 covered by adhesive therefore leaves a non-adhered edge of the patch 27 around its peripheral edge. Because of difficulties in registering the parts of the apparatus and because of the requirement of avoiding the spread of adhesive out on the paper blank beyond the boundary of the transparent patch, it is a practical requirement that the adhesive band 60 of rectangular shape is spaced inwardly from the outer boundary of the area to be covered by the patch 27. Therefore, in Figure 1, as an envelope blank moves to the right over the lower roll 14, the applicator 11 applies the rectangular zone or band 60 of adhesive to the flat blank. As noted, this operation leaves a non-adhered edge portion of the patch along its edge closest to the insertion entrance indicated by the reference character 62 in Figure 9. Mailing material, such as a letter or card inserted into the envelope, may readily hook or catch under this non-adhered edge portion of the transparent patch. As the mailing material is slid into the entrance in a direction laterally of the patch, the catching of the content of the envelope under the non-adhered edge closet to the entrance causes the transparent patch to tear oif, to otherwise tear the envelope, or to cause jamming in the operation of inserting the mailing material. envelopes, slows up the operation of inserting mailing mate-rial, and causes considerable difiiculties as is well known among those acquainted with the use of window envelopes and the insertion of material therein.

, I provide means for closely adhering the edge of the patch closest to the insertion entrance to the inner wall of the envelope so that there is no non-adhered edge portion or pocket under which mailing material may catch or engage.

A reservoir 16 containing gum or other suitable adhesive 17 is positioned as shown in Figure l. A first feed roll 18 driven by a chain 19 which in turn is driven by a motor 20 continuously revolves in the reservoir 16 so as to carry a coating or film of the adhesive on its cylindrical surface. An adjusting mechanism denoted generally by the reference character 21 is carried by the reservoir 16 and scrapes the cylindrical surface of the roll 18 to provide a film of predetermined thickness on the roll 18. A second cylindrical roll 22 is in rolling contact with the roll 18 so as to be driven thereby. The relation of the rolls 18 and 22 is such that the roll 22 is moved in a counterclockwise direction as the roll 18 is driven in a clockwise direction. Of course, adhesive from the roll 18 is transferred to the roll 22 and in this way a continuous film of adhesive is fed to and maintained on the second roll 22.

A continuous band or strip of transparent sheet material 24, such as cellophane or other relatively transparent paper or film, is advanced by a roller 23 as seen in Figure l. The strip of material passes from the feeding roller 23 through a guide 25. A reciprocating knife or cutter blade 26 recurrently descends adjacent the guide or block 25 to cut off the long film of material 24 into pieces or patches 27. The increment of sheet material cut off in each reciprocating cutting motion of the blade 26 is equal to the short width of a transparent patch 27. In this way a succession of individual patches 27 of transparent sheet material are advanced at a first station, this first station being located at the point of severance of the patches from the long strip material 24. For the purpose of the discussion the location of the advancement of separate patches into the apparatus will be referred to as the first station or patch-advancing station.

A roll 28, as seen in Figures 1 and 2, is positioned below the blank carrying belt 15. This lower cylindrical roll 28 has a recess 01' notch 29 formed therein to relieve the cylindrical surface of the roll 28 at the location of the trailing edge of the patch 27 as seen in detail in Figure 2. By means of the recess 29 adhesive would not be applied to the roll 28 if by accident there should be the omission of a blank 57 and patch 27 in the location as shown in Figure 2..

This causes considerable loss in Directly above the roll 28 is positioned an adhesive applicator arranged for the applying of adhesive to the trailing edge portion of a patch 27 as it is advanced from the first or patch-advancing station past the adhesivegathering or second station at the roll 22 to a third station where the patch is applied to the envelope blank as illustrated in Figure 2. A hollow shaft 31 is carried by the frame of the apparatus, and it is driven to rotate in synchronization with the other portions of the apparatus by cams or other well-known synchronizing mechanism, not shown. The shaft 31 has an axial opening 32 extending therein. A pair of yokes 33 and 34 together embrace the shaft 31 at a position intermediate its ends. The yokes 33 and 34 are held together and are keyed to revolve with the shaft 31 by the key or lock 35. Thus, as the shaft 31 rotates, the assembled members 33 and 34 revolve with it. At the lower end of the yoke 34, as seen in Figure 3, a pivot pin 38 extends therethrough. Pivotally mounted on the pin 38 is an arm 37 extending both forwardly and rearwardly of the pivot pin 38. Upon the end of the arm 37, extending upwardly and forwardly from the shaft 31 as seen in Figure 3, is a patch-carrying member or first member 36. This member 36 is adapted to carry successive patches 27 from thefirst or patch-advancing station past the adhesive gathering or second station to the patchapplying or third station. An adjusting screw 39 adjusts the relative position of the arm 37; and hence, the relative position of the member 36 is carried thereon relative to the axis of the shaft 31. A spring 40 biases the rear end of the arm 37 such as to hold the member 36 outwardly from the axis of the shaft, the distance from the axis to the shaft being determined by the setting of the adjusting screw 39.

A patch-engaging or second member 41 is carried by a pair of arms 45, which arms are pivotally carried on the pivot pin 38. The arrangement is such that the member 41 follows and generally moves with the movement of the patch-carrying member 36 upon rotation of the shaft 31. The member 41 is thus pivoted on the same pin 38 so that it may move outwardly from the axis of the shaft 31 independent of the position of the member 36 relative to the same axis. Mounted upon the member 41 and transversely of the apparatus, that is parallel to the axis of the shaft 31, is a rubber edge member 42. As seen in the views of the drawings, theedge member 42 is similar to a rubber wiper blade and is used for pushing or pressing successive patches. 27 away from the axis of the shaft 31 toward the roll 22 upon which a film of adhesive is continually fed. The member 41 is hollow, having a chamber 43 extending along its length, that is transversely of the apparatus. A plurality of small orifices or openings 44 communicate with the chamber 43 and open to atmosphere adjacent and just rearwardly of the edge member 42. Compressed air in the chamber 43 of the second member 41 blows out through the plurality of orifices 44 extending along the length of the member 41, and blows a patch 27 carried by member 36 toward and against the cylindrical surface of the roll 22.

A hose 51, as seen in Figure l, is connected to the axial opening 32 in the shaft 31. At one end of the hose 51 a source of compressed air is connected to communicate with the axial opening 32 and to thus feed compressed air into the axial opening 32 from whence it is delivered into the hose 51. The other end of the hose 51 is connected by the connecting member 58 to a rubber tube or bellows 46 which is positioned immediately to the rear of the member 41 as seen in Figures 3, 4, and 5. The other end of the rubber tube or bellows 46 is connected to the member 41 and communicates with the chamber 43 therein. The rubber tube or bellows 46 is relatively soft and pliable so as to be deformable.

A spring 49 is attached to the member 41 and has an end anchored to a bracket 48. A backing plate 47 is secured by welding or other means to the bracket 48 and has its forward end extending to the side end centrally of the bellows 46 as illustrated in Figures 3 and 5. The bias of the spring 49 is such as to resiliently press the member 41 toward the backing plate 47 and to thus deform or squeeze the bellows 46. However, this bias of the spring 49 may be overcome by the admittance of compressed air into the bellows 46 through the connecting member 50,

hose 51, axial opening 32, from the source of compressed air. Therefore, when there is no compressed air admitted to the bellows 46, the spring 49 moves the member 41 and with it the edge member 42 away from the roll 22 and toward the axis of the shaft 31. Upon admittance of a surge or blast of compressed air into the bellows 46, the bellows 46 tends to bend toward its cylindrical form and to thus move the member 41 and edge member 42 toward the roll 22 and to thus repel or press the trailing edge portion of a patch 27 toward the film of adhesive on the cylindrical surface of the roll 22. At the same time that the blast of air is admitted to the bellows 46, it flows into the chamber 43 of the member 41 and hence, out through the plurality of small orifices 44 back of the edge member 42. The many small streams of compressed air out through the orifices 44 blow the trailing edge portion of the patch 27 that follows the edge member 42 outwardly against the roll 22. When the blast of. compressed air ceases, the spring 49 again causes the. member 41 to swing back on the pivct of the pin 38 toward the axis of the shaft 31, and hence, away from the roll 22. Also, the cessation of the blast of compressed air terminates any outward blowing on the trailing edge portion of the patch 27.

By a suitable cam or other synchronizing means, not shown, the blast of compressed air is turned on and off as required in the cycle of operation. When in the position of Figure l, the air blast would not be turned on; and hence, the member 41 would be in a relatively retracted position and no streams of compressed air would be coming from the orifices 44. However, when in the relative position of Figure 3 when the patch 27 is to gather adhesive from the roll 22, then there is a blast of compressed air admitted through the hose 51 to the bellows 46 and out through the orifices 44. Preferably, the blast of compressed air is continued until the parts have reached the relative position shown in Figure 2 wherein the patch 27 is being applied to the envelope blank 57, and in this way the trailing edge portion of the patch 27 is firmly pressed down upon the blank to cause a good bond between the patch and the blank along the trailing edge of the patch, this trailing edge coinciding with the edge which is closest to the insertion entrance 62 of the complete envelope as shown in Fi ure 9.

To hold the successive patches 27 to the patch carrying member 36 in its recurrent movement from the first station past the second station to the third station suction means are provided. A plurality of small suction orifices 52 extend across the face of the member 36 as shown in Figures 3 and 4. These orifices 52 communicate with a chamber or transverse conduit 53 within the member 36. This chamber 53 in turn communicates with a duct 54 extending out to the rear of the member 36. A connecting member 55 communicating with the duct 54 provides communication with a hose, not shown, which is placed in communication with a source of vacuum or negative air pressure. For purpose of simplicity in illustration the hose connecting the connection 55 with a source of suction or negative air pressure is not shown. Preferably, a portion of the axial opening 32 is blocked off from the portion through which air pressure is communicated through the hose 51, and this other portion of the axial opening 32 is attached to the hose adapted to be connected to the connection 55. The other end of the shaft 31, through which the suction or vacuum is carried, is connected thus to a source of vacuum or air suction. In this way the air pressure to the member 41 and the suction or vacuum to the member 36 may be independently conducted thereto through the shaft 31 while the members are revolving around the axis of 'the shaft 31.

In the operation of my apparatus and in the carrying out of my method, envelope blanks 57 in the fiat are successively carried along the belt 15 over the rolls 14 and 28. The rectangular shaped band of adhesive is placed in the zone 69 around the opening 58 by the applicator 11 as seen in Figures 7 and 8. This rectangular zone of adhesive is spaced inwardly from the peripheral edge of the area occupied by the patch 27. This leaves an un-. bonded or non-adhered flap or edge portion between the patch 27 and the inner wall of the envelope. By passing the envelope over the roll 28 and causing the members 4;. and 36 to revolve around the axis of the shaft 31 in synchrony with the movement of the belt 15 and roll 28, successive patches 27 are carried from the first station past the second station to the third station where the patches are applied to the successive blanks 57. The timing of the valves for turning on the air pressure and turning on the vacuum or air suction is such that as the member 36 reaches the first station, vacuum or air suction is turned on and the vacuum or air suction continues from the first station to the third station "so that the patch is firmly carried rom the first station past the second sta'- tion to the third station Where the vacuum or air suction is terminated by the synchronizing mechanism operating the valves. As the member 41 approaches the second station, that is near the roll 22, the air pressure is turned on by the synchronizing mechanism operating the valves on the source of air pressure so as to expand the bellows 46 and to cause jets of air blast to blow through the orifices 44 against the trailing edge portion of the patch 27 and thus against the film of adhesive on the roll 22. The parts continue on the journey from the second station shown approximately in Figure 3 to the third station shown approximately in Figure 2. Preferably, the. air pressure is continued to the position shown in Figure 2 so that the trailing edge portion of the patch is firmly pressed to the blank. As the parts leave the position shown in Figure 2 to revolve back to the first station, the air suction is terminated so that the patch is left upon the blank without pull thereon. Also, the air pressure is terminated and remains turned off until member 41 again approaches the second station near the roll 22.

By the apparatus shown and described and the method here disclosed, a new and novel envelope as shown in Figure 9 may be produced. Here the zone 61 of adhesive firmly binds the edge of the patch 27 to the inner wall of the envelope so that there is no pocket or loose flap under which mailing material may catch or engage as it is inserted into the envelope through the insertion entrance 62.

The present disclosure includes the description contained in the appended claims as well as the foregoing description and disclosure in the drawings.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by Way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to Without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. Apparatus for gumming the trailing edge portion of a patch of auxiliary sheet material for adherence to a body of principal sheet material, comprising the combination of patch-advancing means for serially advancing said patches, a gum-feeding device, said device including a gum-carrying element, a mechanism carrying said principal sheet material through the apparatus, said mechanism including a roller over which said principal sheet material passes, and means for serially transferring said patches from said patch-advancing means, applying gum to the trailing edge portion thereof and thereafter applying the patch to said principal sheet material passing over said roller, said means including a first member and a second member recurrently movable from said patchadvancing means past said gum-carrying element to said roller, vacuum means associated with said first member for holding by suction successive patches to the first member during said recurrent movement of the first member, and fluid pressure means associated with said second member for moving successive patches toward said gumcarrying element and blowing the trailing edge portions thereof against said gum-carrying element to apply gum to such said trailing edge portion during said recurrent movement of the second member.

2. Apparatus for gumming the trailing edge portion of successive patches of secondary sheet material and applying the patches to primary sheet material moving through the apparatus, comprising patch-advancing means at a first station, gum-feed means at a second station, support means for said primary sheet material at a third station, and a device for successively carrying said patches from said first station past said second station to said third station to apply the successive patches to the primary sheet material moving through the apparatus, said device including fluid suction means for holding a said patch to the device and, fluid pressure means for moving the trailing edge portion of a said patch outwardly from said device.

3. Apparatus for gumming the trailing edge portion of successive patches of secondary sheet material and applying the patches to primary sheet material moving through the apparatus, comprising patch-advancing means at a first station, gum-feed means at a second station, support means for said primary sheet material at a third station, and a device for successively carrying said patches from said first station past said second station to said third station to apply the successive patches to the primary sheet material moving through the apparatus, said device having first orifice means adapted to communicate with a source of fluid suction for drawing a said patch to the device and second orifice means adapted to communicate with a source of fluid pressure for moving the trailing edge portion of said patch from said device toward said gum-feed means at said second station.

4. In apparatus having mechanism for carrying primary sheet material therethrough, advancing means for serially advancing successive patches of secondary sheet material to be adhered to said primary sheet material, and an adhesive-supplier, a device comprising a first member and a second member mounted to a common support in said apparatus and recurrently movable together with said common support through a cycle of the apparatus from said advancing means past said adhesive-supplier to said mechanism to successively carry patches of secondary sheet material to move the trailing edge portion of each patch against said adhesive-supplier to gather adhesive on said trailing edge portion and to apply said each patch to said primary sheet material, said first member carrying the body of each said patch in said recurrent movement to avoid the adhesive-supplier and said second member moving the trailing edge portion of each said patch relative to said first member, against the adhesivesupplier in adhesive-gathering relationship, said second member moving said trailing edge portion at said mechanism against said primary sheet material.

5. In apparatus having mechanism for carrying primary sheet material therethrough, advancing means for serially advancing successive patches of secondary sheet material to be adhered to said primary sheet material, and an adhesive-supplier, a device comprising a first member and a second member mounted to said apparatus and recurrently movable together from said advancing means past said adhesive-supplier to said mechanism to successively carry patches of secondary sheet material to move the trailing edge portion of each patch against said adhesive-supplier to gather adhesive on said trailing edge portion and to apply said each patch to said primary sheet material, holding means carried by said first member and in communication with a source of relative vacuum for holding by suction the body of each said patch to the first member during each recurrent movement, and repelling means carried by said second member for repelling the trailing edge portion of each said patch relative to said first member to gather adhesive thereon from said adhesive-supplier, said holding means holding the body of the patch away from said adhesive-supplier during each recurrent movement, said repelling means urging the said trailing edge portion having adhesive gathered thereon toward said primary sheet material at said mechanism.

6. In apparatus for applying patches of transparent sheet material to envelopes each having an opening over which a patch is to be placed for forming a window therein, in which each envelope passing through the ap paratus has patch-holding adhesive applied in a Zone located around said opening and spaced from the edge of the patch closest to the flap thereof and which is the trailing edge of the patch as it is applied to an envelope, said apparatus including a first station where successive being adapted to said patches are obtained, a second station where adhesive may be gathered, and a third station where patches are successively applied to said envelopes, the improvement of mechanism for applying adhesive to the portion of each patch adjacent its trailing edge to provide a bond between the patch and envelope along said edge, comprising a revolvable first member revolvable about an axis and adapted to carry successive patches from said first station past said second station to said third station, said first member being revolvable in an arc avoiding adhesive at said second station, a revolvable second member revolvable about the said axis and arranged to follow and move in synchrony with said first member, said second member engaging a said'patch adjacent said edge and being movable in an are greater than the are through which said first member moves in the region of said second station to carry said patch portion in said greater are to gather adhesive thereon at said second station in its movement to said third station.

7. In apparatus for applying patches of transparent sheet material to envelopes each having an opening over which a patch is to be placed for forming a window therein, in which each envelope passing through the apparatus has patch-holding adhesive applied in a zone located around said opening and spaced from the edge of the patch closest to the flap thereof and which is the trailing edge of the patch as it is applied to an envelope, said apparatus including a first station where successive said patches are obtained, a second station where adhesive may be gathered, and a third station where patches are successively applied to said envelopes, the improvement of mechanism for applying adhesive to the portion of each patch adjacent its trailing edge to provide a bond between the patch and envelope along said edge, comprising, first means mounted to said apparatus to recurrently move from said first station past said second station to said third station, second means carried by said first means adapted to communicate with a source of air suction and adapted to hold a said patch to said first means during said recurrent movement, third means mounted to said apparatus to recurrently move from said first station past said second station to said third station following and in synchrony with said first means, said third means engage the portion of each patch adjacent its trailing edge, fourth means for moving said third means toward said second station, and fifth means carried by said fourth means and adapted to communicate with a source of air under pressure, said fourth and fifth means being arranged to bias said patch portion toward said second station to gather adhesive thereon during said recurrent movement.

8. In apparatus for applying patches of transparent sheet material to envelopes each having an opening over which a patch is to be placed for forming a window therein, in which each envelope passing through the apparatus has patch-holding adhesive applied in a zone located around said opening and spaced from the edge of the patch closest to the flap thereof and which is the trailing edge of the patch as it is applied to an envelope, said apparatus including a first station where successive said patches are obtained, a second station where adhesive may be gathered, and a third station where patches are successively applied to said envelopes, the improvement of mechanism for applying adhesive to the portion of each patch adjacent its trailing edge to provide a bond between the patch and envelope along said edge, comprising, first means mounted to said apparatus to recurrently move in an arcuate path from said first station past said second station to said third station, second means carried by said first means adapted to communicate with a source of air suction and adapted to hold the body of a said patch to said first means during said recurrent movement and away from said second station as the first means moves past the second station, third means mounted to said apparatus to recurrently move from said first station past said second station to said third station following and in synchrony with said first means, said third means being adapted to engage the portion of each patch adjacent its trailing edge, and biasing means carried by said third means for biasing the traliing edge portion of said patch portion outwardly from the arcuate path of said first means toward the second station to gather adhesive on the said trailing edge portion and toward the third station to move said trailing edge portion against a said envelope.

9. The method of making window envelopes having an insertion entrance from paper envelope blanks having an opening therein and from patches of transparent sheet material, comprising the step of applying adhesive to each blank around the said opening, said adhesvie being applied inwardly from the boundary of the patch to be applied, applying adhesive to the trailing edge portion of each said patch on the side thereof to meet the respective blank as the patch is advanced toward the said blank, and applying the said patch to the respective blank to position the boundary of the patch outwardly of the adhesive applied to the blank and to position the adhesive applied to the trailing edge portion of the patch laterally outwardly of said adhesive applied to the blank and away from said opening and closest to said insertion entrance to closely bond said edge portion to said blank at said edge portion.

10. In the making of window envelopes from paper blanks having window openings and from patches of transparent sheet material adhered to the inner wall of the respective envelopes to cover the openings, each envelope having an entrance for insertion of material movable toward the edge of the patch and laterally of said patch, said blanks having adhesive applied inwardly from the boundary of the patch to be applied and around said opening thereof, the improvement of applying adhesive to the trailing edge portion of the patches successively advanced toward the respective blanks on the side of the patches to face the respective blanks and of adhering the patches to the respective blanks with the boundary of the patches positioned outwardly of the adhesive applied to the respective blanks, including the positioning and adhering of said trailing edge portion of the patches to the respective blanks along the side of said opening closest to said insertion entrance of the respective envelopes and laterally outwardly of the adhesive applied to the respective blanks.

11. Apparatus for gumming the trailing edge portion of a patch of auxiliary sheet material for adherence to a body of principal sheet material, comprising the combination of patch-advancing means for serially advancing said patches, a gum-feeding device, said device including a gum-carrying element, a mechanism carrying said principal sheet material through the apparatus, said mechanism including a roller over which said principal sheet material passes, and means for serially transferring said patches from said patch-advancing means, applying gum to the trailing edge portion thereof and thereafter applying the patch to said principal sheet material passing over said roller, said means including a first member and a second member recurrently movable together from said patch-advancing means past said gum-carrying element to said roller, vacuum means associated with said first member for holding by suction the bodies of successive patches to the first member during said recurrent movement of the first member and out of contact with said gumcarrying element, and means associated with said second member for moving the trailing edge portion of successive patches toward said gum-carrying element to apply gum to said trailing edge portion during said recurrent movement of the second member and toward said roller to press the said trailing edge portion toward said principal sheet material.

12. Apparatus for gumming the trailing edge portion of successive patches of secondary sheet material and applying the patches to primary sheet: material moving through the apparatus, comprising patch-advancing means at a first station, gum-feed means at asecond station, support means for said primary sheet material at a third station, and a device for successively carrying said patches from said first station past said second station to said third station to apply the successive patches to the primary sheet material moving through the apparatus, said device including means for holding the body of a said patch to the device away from said second station and means for moving the trailing edge portion of a said patch outwardly from said device toward said second station to gather gum thereon and toward the third station to adhere to said sheet material.

13. Apparatus for gumming the trailing edge portion of successive patches of secondary sheet material and applying the patches to primary sheet material moving through the apparatus, comprising patch-advancing means at a first station, gum-feed means at a second station, support means for said primary sheet material at a third station, and a device for successively carrying said patches from said first station past said second station to said third station to apply the successive patches to the primary sheet material moving through the apparatus, said device having orifice means adapted to communicate with a source of fluid suction for drawing the body of a said patch to the device and away from said gum feed means and recurrently operable means for moving the trailing edge portion of said patch toward said gum-feed means more than the remainder of said patch to gather gum only on said trailing edge portion of said patch at said second station and toward said support means at said third station to adhere said trailing edge portion to said sheet material.

14. In apparatus for applying patches of transparent sheet material to envelopes each having an opening over which a patch is to be placed for forming a window therein, in which each envelope passing through the apparatus has patch-holding adhesive applied in a zone located around said opening and spaced for the edge of the patch closest to the flapthereof and which is the trailing edge of the patch as it is applied to an envelope, said apparatus including a first station Where successive said patches are obtained, a second station where adhesive may be gathered, and a third station where patches are successively applied to said envelopes, the improvement of mechanism for applying adhesive to the portion of each patch adjacent its trailing edge to provide a bond between the patch and envelope along said edge, comprising, first means mounted to said apparatus to recurrently move from said first station past said second station to said third station, second means carried by said first means adapted to communicate with a source of air suction and adapted to hold the body of a said patch to said first means during said recurrent movement and away from said second station, third means carried by said first means to recur-rently move from said first station past said second station to said third station following and in synchrony with said first means, said third means being adapted to engage the portion of each patch adjacent its trailing edge, and fourth means for moving said third means toward said second station relative to said first means, said fourth means being arranged to bias said portion of each patch toward said second station to gather adhesive thereon during said recurrent movement and toward said third station to adhere said portion to a said envelope.

Marston et al. Oct. 24, 1916 Aug. 1 3, 1918 (Other references on following page) 11 UNITED STATES PATENTS Swift Aug. 27, 1918 Heywood" Sept. 21,1920 Funk Mar. 22, 1921 Cheetham Dec. 16, 1924 Wettlaufer Aug. 13, 1935 Gray Dec. 14, 1937 Berkowitz Q. May 24, 1938 Gray May 16, 1939 Pearce Aug. 15, 1939 Noyick Sept. 26, 1939 -La Bombard May 28, 1940 Elsner Jan. 8, 1952 Halahan et a1 Sept. 28, 1954 

